As shown in U.S. Pat. No. 3,224,684 issued to V. D. Roosa on Dec. 21, 1965, some fuel injection nozzles each have a side-entry fuel inlet stud which is brazed or welded to a body of the fuel injection nozzle. Such inlet connections are desirable because the inlet stud is easily bendable to adapt the fuel injection nozzle to a variety of engine applications where the free space allotted for location of the fuel injection nozzle is very limited.
One disadvantage of the above brazed or welded connection is that it is difficult to repeatedly ensure that the brazing or welding material, such as silver or copper solder, adequately penetrates the joint. Consequently, a significant portion of fuel injection nozzles manufactured generally according to this method fail to pass a required fuel leakage test and consequently must be either reworked or scrapped. Another disadvantage of the above brazed or welded connection is that the heat applied during brazing or welding can distort and consequently prevent proper operation of the needle check guide and/or the needle check of the fuel injection nozzle if the needle check guide was already made integral with the body. One approach to solving this problem is shown in U.S. Pat. No. 3,255,974 issued to V. D. Roosa on June 14, 1966 where a separate precision-ground guide for the needle check is installed in the body after the inlet stud has been brazed to the body. However, providing the needle check guide as a separate part relative to the body makes this approach more costly than an integral design.
Another approach to minimizing the above problems is to eliminate such brazed or welded joints as shown in U.S. Pat. No. 4,163,521 issued to V. D. Roosa on Aug. 7, 1979. In the above disclosure, an inlet fitting is shrunk or press fit around the body without welding. A fuel supply line is then connected to the inlet fitting by a collar and a threaded tubular fitting. Other types of threaded connections between a fuel supply line and the body of a fuel injection nozzle are shown in U.S. Pat. No. 2,365,752 issued to H. C. Edwards on Dec. 26, 1944 and U.S. Pat. No. 4,266,728 issued to J. R. Voss et al. on May 12, 1981.
A disadvantage with all of these types of threaded connections is that their size may make the fuel injection nozzle exceed the space available for a particular installation. For example, often there is not enough room in an engine compartment, due to the crowding presence of a valve train and/or the limited size of a valve-train cover, to accommodate such threaded connections which must be large enough in size to withstand high-pressure fuel leakage.
The present invention is directed to overcoming one or more of the problems as set forth above.